Shock absorber



I i II: I

Sept 2 c. A; STICKNEY 5300K ABSORBER Filed Oct. 19, 1925 Patented Sept.20, 1927.

UNITED STATES PATENT. OFFICE. 7

CHARLES A. STICKN'EY, OE ROCKFORD, ILLINOIS, ASSIGNOR TO ROCKFORDDRILLING MACHINE CO MPANY, 0F ROCKFORD, ILLINOIS, A CORPORATION OFILLINOIS.

SHOCK ABSORBER.

Application filed October This invention relates to shock absorbers formotor vehicles,

One of the principal objects of the invention is to provide a simplifiedand generally 5. improved shock absorber operating to allow freedeflection of the vehicle springs when the wheels pass over rough placesin the road but serving to retard or check the rebound or recoil actionof the springs, the la means employed consisting preferably of aninternal expanding brake band operating inside an external rotary drumand mounted so it wraps or contracts when the drum turns in onedirection in the deflection of the vehicle springs, but unwraps orexpands into tight frictional braking engagement with the drum when thelatter turns in the opposite direction in the rebound.

Another important object is the provision of an internal expanding brakeband supported on the outside of a stationary drum and having anexternal rotary drum supported directly by its contact on the brakeband, the arrangement obviating the necessity for lubrication at anypoint in the entire structure and providing a device which is immune tothe action of'moisture and dirt so far as its etlicient operation isconcerned, although the construction of the device is such aspractically to preclude moisture or dirt from entering.

Still another important object of this invention is the provision inconnection with the rotary drum and the internal expanding brake band,of a single torsion spring serving the double purpose of retrieving theflexible cable winding on the drum, and maintaining constantly a certainpressure on the brake band tending to expand the same into closefrictional contact with the inside of the drum. It is a further featureof my invention to arrange the spring with refer ence to the drum andbrake band so that very little pressure is applied to expand the brakeband during the deflection of the vehicle springs, when the flexiblecable-is being retrieved in the unwinding of the torsion spring, andwhereby, on the rebound, when the torsion spring is rewound, it exertsincreasingly greater pressure on the brake band to expand the same intocloser frictional contact with the drum. The latter feature enablesadapting my shock absorbers to cars of different Weight since theinitial spring tension may be adjusted to 19, 1925. Serial No. 63,206.

secure different degrees of snubbing effects. Still another feature ofthe invention is to provide a shock absorber constructed so far aspracticable of stamped or drawn sheet metal parts with a view tosecuring a more compact, light and economical device. The foregoing andother objects of the lnvention are pointed out in the following detaileddescription in which reference is made to the accompanying drawingillustrating my invention. In the drawing Fig. 1 is a side viewof ashock absorber made in accordance with my invention shown mounted on achassis part of a motor vehicle and connected with the axle or axlehousing or other relatively movable part of the vehicle;

Fig. Qis a central vertical cross section through Fig. 1 taken on theline 22 thereof;

Fig. 3 is a transverse vertical section taken on the line 33 of Fig. 2;and

Fig. 4 is'another similar section taken on the line 44 of Fig. 2,

All of the sections are taken looking in the direction of the smallarrows and throughout the views the same reference numerals are appliedto corresponding parts.

Referring to the drawing, the shock absorber 5 is supported on a hanger6 bolted, as shown at 7, or secured in any other manner, to the chassisframe 8 or some other part moving with the chassis. The flexible cableor strap 9 of the shock absorber extends therefrom for connection withthe axle 10.. In the illustration one end of the cable 9 is shownwrapped about the axle housing .11 and secured by a suitable clampingdevice 12. The operation of shock absorbers, snul bers, and similarretarding or checking clevices used on motor vehicles is quite commonlyknown, so that it will suflice to state at this point that, in thedeflection of the vehicle springs caused by the wheels passing over arough place in the road, the chassis 8 moves freely toward the axle 10and suitable means is provided in the shock absorber 5 to take up theslack in the cable 9. Then, on the rebound, when the chassis 8 movesaway from the axle 10 under the recoil or rebound action of thesupporting springs, the shock absorber is operated to check the movementof the chassis,

Referring for the presentmore particularly to Figs. 3 and at, the shockabsorber a zero value.

comprises essentially an outer rotary drum 13, an inner fixed drum 14,and an internal expanding brake band 15, supported throughout its lengthon the outside of the inner fixed drum 14 and frictionally engagingthe-inner periphery ot-the outer drum .13. The brake band is fixed atthe oneend, as shown at 16, by rivets passing through the flange of thedrum 14, and has its other end free. A spiral torsion spring 17 isarranged normally to tend to turn a disc 18 in one direction undervarying torque, there being a certain initial or residual torque in thespring in the most unwound condition thereof. .The disc 18 tends to turnin a clockwise direction, asseen in Fig. 4, and causes the lug 19thereof to bear upon the free end of the brake band 15to tend to expandthe same into close frictional contact with the internal periphery ofthe outer drum 13. The spring 17 furthermore tends normally to turn thedrum 13 in a counterclockwise direction, as seen in Fig. 4, normally toretrieve the cable 9. When a defiection of the vehiclesprings occurs andthe chassis 8 and the axle 10 move toward each other, the drum 13 turnsin a counter-clockwise direction and winds up the cable 9 to permitnoslack to occur therein. Obvious- 1y, during this oaeration the torueof the spring 17 is partly dissipated, anc, as a result, the pressurewith which the lug 19 engages the free end of the brake band 1s somewhatlighter; never, however, reaching On the rebound, the spring is rewoundin the unreeling of the cable, and, consequently the resulting greater.torque of the spring is accompanied with greater pressure applied tothe free end of the brake band by the lug 19. Furthermore, it will beseen that the-torque stored in the spring increases proportionally thefarther apart the chassis 8 and the axle 1O become, so that there is anaccompanying greater braking eltectexerted by the brake band 15, as aresult of the increasing pressure of the lug 19 as the spring is woundup more and more. From the description thus far advanced, it will appearthat there is relatively no braking or retarding effect produced by theshock absorber during the deflection of the vehicle springs. This is duepartly to the fact that there is relatively little pressure applied bythe lug 19 to the free end of the brake band, because of the unwoundcondition of the spring 17 which, as a matter of fact, exerts less andless torque the more the chassis 8 approaches the axle 10. Moreparticularly, however, this is due to the fact that the drum 13 rotatesin a counter-clockwise direction and there is a tendency for the brakeband to wind up or contract. Vere it not for the pressure applied by thelug 19, the band would lie practically free of the drum but, as it is,it exerts only a slight frictional drag ofno appreciable ettect. On therebound the drum turns in a clockwise direction and two factors enter tocommunicate a heavy braking or retarding effect; the increased andincreasing torque ing effect produced, so that there is a building up ofbraking action reaching very etiective proportions. The farther thechassis 8 becomes removed from the axle 10,-the greater the torque ofthe spring 1'? becomes, and, as a result, there is increasing pressure01 the lug 19 on the free end of the brake band to secure more and moreretarding or checking action.

I have chosen to set forth thusly. in a general way, the operation ofmy'device inasmuch as I realize that the principle involved is importantapart from the details of any form of structure which may be devised toembody the operations described. The following detailed description of aparticular embodiment of my invention will not therefore be understoodas limiting the invention in any wise to the particular detailsillustrated. The inner fixed drum I prefer to provide in two sections 14and 14 mounted on the opposite ends of a'stud 20 projecting from theside of the hanger 6.

The stud 20 is in the form of a bolt the head of which sets in adepression 21 in a side'plate 22, between the plate 22 and the side ofthe hanger 6. The plate 22 is riveted, as shown at 23 and 24, with thedrum section 14 to the hanger 6, an intermediate strengthening washer 25being interposedbetween the plate 22 and the drum 14 as illustrated. Theparts just referred to are stamped or drawn sheet metal. The drumsection 14, in a similar manner. is riveted.

at 23 and 24' to the opposite side plate 22 and has an intermediatestrengthening; member 25, interposed between the druiii sectionand theside plate. A nut 26 threadmg on the stud 2O secures the drum sectionsagainst relative, rotation and in rigidly spaced relation on theopposite ends of a sleeve 27, fitting about the stud 20 and havin greduced squared ends 28 fitting in square openings in the drum sections.The drumsection 14, being riveted with the hanger 6, the section 14 ismaintained in the same relation through the medium 01 the s eeve 27, inan obvious manner. The outer drum lit) I prefer to provide in twosections 13 and 13, of cupped form similarly as the inner drum sections14- and 14, and formed of side walls of the groove provided by the drumsections. The brake band isalso provided in two sections 15 and 15,disposed between the inner and outer brake drum sections. The spring 17has its outer end forked, as indicated at 35, to receive a crosspin 36passing through the ring 30 and the inturned flanges of the drumsections 13 and 13, whereby to connect the one end of the spring 17 withthe outer brake drum. The inner end of the springl? is riveted, as shownat 37, to a tube 38. The latter surrounds a plurality'of pins 39extending crosswise between the tube 38 and the sleeve 27, and engagingin openings provided therefor in the discs 18 and 18. The head of therivet or rivets 37 engages one of the pins 39 to communicatepressure inaclockwisedirection, as the pins are seen in Fig. and thereby to exert ayielding pressure tending to turn the discs 18 and 18 in a clockwisedirection, as seen in Fig. 4. The lugs 19 and 19 of the discs arereceived in elongated notches 10 and 4:0 in the inturned flanges of thedrum sections 1 1 and 1 1 and arranged to have a certain degree of freemovement therein while in engagement with the ends of the brake bands 15and 15respectively, in the manner above described. The discs 18 and 18are free to turn on the sleeve 27 so that whatever torque resides in thespring 17 is communicated to the scription except to point out featuresre lating to the structure of my improved shock absorber not previouslyreferred to. It will be seen that the provision of an illternal drum,and an external drum riding on and supported by an internal expandingbrake band, in turn supported on the inner drum. dispenses with theusual provision of relatively moving parts which require lubrication.The only relatively moving parts are the outer drum and the brake band.These. obviously, should have no lubrication. Furthermore, all of theoperating parts are fully enclosed so that dirt and. moisture arepractically excluded. However, such dirt or moisture as will enter thedevice, will not affect its operation in any manner, unless perhaps toincrease the snubbing, retarding, or checking action by virtue of theincreased friction resulting between the relatively moving parts. These,as stated before, are only the outer drum and the brake band. The onlypartssubject to wear are, of course, the brank band, and,'t'o a smalldegree, the outer drum. The arrangement of two outer drum sections andtwo brake band sections to either side of the operating cable affords amaximum friction surface. The provision, so far as practicable, ofstamped and drawn parts tends toward. compactness, lightness, andcheapness, as well as durability.

I claim:

1. In a shock absorber, a revoluble drum mounted on one of tworelatively movable members, a flexible element affixed to and winding onsaid drum and afiixedat its free end to the other member, spring meansnormally turning said drum in one direction to take up slack in saidflexible element, and a brake band operating on said drum and heldnormally by said spring means toward braking engagement with said drum,said band being operable under slight unappreciable load existing insaid spring means during a deflection of the vehicle springs which isaccompanied with a moving together of said aforementioned members, andbeing operable under a heavier load existing in said spring means duringa rebounding movement, which is accompanied with a moving apart oftheaforementioned members.

2. In a shock absorber, a revoluble drum mounted on one of tworelatively movable members, a flexible element aflixed to and winding onsaid drum and affixed at its free end to the other member, spring meansnormally turning said drum in one direction to take up slack in saidflexible element, and a brake band operating on said drum and heldnormally by said spring means toward braking engagement with said drum,said band being operable under slight unappreciableload existingin saidspring means during a deflection of the vehicle spring, which isaccompaniedwith amoving together of said aforementioned members, andbeing operable under a heavier appreciable load existing in said springmeans during a rebounding movement, which is accompanied with a movingapart of the aforementioned members, the loading of said spring meansincreasing with the movement of said members farther apart and giving aresulting increased braking effect through said brake band. I

3. In a shock absorber, the combination-of an internal expanding brakemechanism, a support therefor, an external drum rotatably supported, bythe; brake mechanism, a flexible element aflixed 'to said drum andwinding thereon and affixed at its free end to a part movable withreference to said shock absorber, and spring means normally turningsaiddrum in one direction to take up slack in said flexible element,said brake mechanism being non-eflective during the winding up of theflexible element in a deflection of the vehicle springs butbeing-effective on the unreeling thereot during-rebound, theeffectiveness or non-effectiveness of said brake mechanism dependingpartly on the existence of tension in said spring means.

4. In a shock absorber, the combination oi? an internal expanding brakemechanism, a support therefor, an external drum rotatably supported bythe brake mechanism, a flexible element aflixed to said drum and windingthereon and aflixed at itsi'i'r'ee end to a part movable with referenceto said shock absorber, and spring means normally turning said drum inone direction to take up slack in said flexible element, said brakemechanism being non-effect1ve during the winding up of the flexibleelement in a defleotion of the vehicle'sprin'gs but being etl'ective onthe unreeling thereof during rebound, the effectiveness ornon-effectiveness of said brake mechanism depending partly on theexistence of tension in said spring means, and being less andless'etfective in .the course of the deflection movement, due to therebeing less and less tension" in the spring means, and being more andmore effective in the course or" a rebound movement, due to there beingmore and more tension in the spring means.

5. In a shock absorber, the combination" end of said brake band, andmeans operat ing under the load stored 1n said spring means foryleldingly engaging the free end of said band to exert a tendency vforexpanding the same. 7 V

6. In a shock absorber, the combination of an inner stationary drum, anouter telescoping rotatable drum, a brake band supported between saiddrums fixed at oneend to the outside of said stationary drum andarranged to expand into operating'engage ment with the inner peripheryof said outer drum, a flexible element winding on and fixed to saidouterdrum and having its free end affixed to a part movable withrespect tosaid shock absorber, a torsions'pring having one end fixed to andmovablewithithe outer drumtending normally to turn the same in one direction toretrieve said flexible element, and. a part operated by the other end ofsaid spring into engagement with the free end of said brake band tendingnormally to move the end of said band in a direction to expand the sameinto operating engagement with said outer drum.

7. Ina shock absorber, the combination or" an inner stationary drum, anouter tele scoping rotatable drum, a brake band sup ported between saiddrums fixed at one end to the outside of said stationary drum andarranged to expand into'operating engagement with the inner periphery ofsaidouter drum, a flexible element winding on and -11,

end of said s arin into en agement witlrthe 1 P": C L) 7 tree end oisaid brake band tending normally to move the end of said band in adirection to expand the same into operating engagement with said outerdrum, said spring in operation exerting less and less pressure on saidpart as it turns said drum to recoil said flexible clement duringdeflection ot the vehicle springs and exerting more and more pressure onsaid band as said drum turns to unrcel the flexible element in the rebound of the vehicle. r

8. In a shock absorber, the combination of a pair of inner drums spacedlaterally with their flanges facing, a pair of telescoping outer drumshaving their flanges extending in opposed relation concentric with theflanges of said inner dr nns. a pair of brake bands between said'drumshaving their oneends fixed to the inner drums, a pair of discs havinglugs engaging the free ends of said brake bands to move the same in onedirection to expand the bands into operating engagement with the insideof said outer drums, a torsion spring having one end fixed to andmovable with the outer drums and'having its other end urging in adirection to expandfsaid bands, and a flexible element having one endfixed to said outer drums and having its other end affixed to' a partmovable with respect to said shock absorber to turn said drums in onedirection against the action of said spring when said partmoves withrespect to Said shock absorber.

9. In a shockabsorb-er, the combinationof a pair of inner drums spacedlaterally with their flanges facing, a pair of telescoping outer drumswith their flanges extending in opposed relation concentric with" theflanges of said inner drums; a pair ofbrake bands between said drumshaving their one ends fixed to the inner drums, a pair ofsaid discs 1st)i lit) outer drums and having its other end affixed to a part movablewith respect to said shock absorber to turn said drums in one directionagainst the action of said spring when said part moves with respect tosaid shock absorber, said outer drums being connected but arranged inlaterally spaced relation leaving an annular recess therebetween on theoutside of said shock absorber for the reception of said flexibleelement.

10. In a shock absorber, a hanger to serve as a fixed support, a pair ofinner drums mounted in fixed spaced relation on said hanger with theirflanges facing, a pair of outer movable drums fixed together betweensaid inner drums with their flanges ex tending in opposed relation andin concentrio relation with the flanges of said inner drums, brake bandsfixed at one end on each of said inner drums and lying between saidinner and outer drums, a pair of laterally spaced and relatively fixeddiscs having lugs engaging the free ends of said brake bands to move thesame in one direction to expand said bands into operating engagementwith said outer drums, a torsion spring mounted between said discs withits outer end fixed to said outer drums and its inner end connected withsaid discs to move the same normally in one direction to expand saidbrake bands, and a flexible element having one end fixed to said outerdrums and having its other end affixed to a part movable with respect tosaid shock absorber.

11. In a shock absorber, the combination of an inner drum, an outer drumtelescoping therewith, said drums being mounted for relative rotationwith respect to one another, one of said drums being mounted on one oftwo relatively movable members and the other of said drums havingconnection with the other of the two relatively movable members wherebyto produce relative rotation of the drums when the members move withrespect to one another, spring means arranged to be placed under loadwhen the members move apart, a brake band mounted on one of said drumsand frictionally engaging the other of said drums, and means connectingsaid band with said spring means whereby an increase in the load on thespring means increases thebraking action of the band.

12. In a shock absorber, the combination with the other of the tworelatively movable members whereby said drums are arranged tohaverelative rotation in the movement of one member relative'to the other,an expanding brake band mounted on the inner drum for frictiona-llyengaging the outer drum to exert a braking ction, spring means placedunder load when the relatively movable members move apart, and meanssubject to the load of said spring means acting to expand said brakeband toward braking engagement.

13. In a shock absorber, the combination of a pair of relativelyrotatable telescoping drums, one of said drums being mounted on one oftwo relatively movable members and the other of said drums beingconnected with the other of the two relatively movable members wherebyto produce relative rotation of said drums inthe movement of one memberrelative to the other, an internal expanding brake band mounted on theinner drum to have frictional engagement with the inside of the outerdrum, and means for fixing one end of said band to the inner drum, theother end of said band being free for expansion or contraction of theband, said band being arranged with respect to said drums whereby whenthe outer drum turns in one direction in the deflection of the vehiclesprings said band tends to wrap and consequently contract so as to exertlittle or no braking effect but arranged when the outer drum is turnedin the opposite direction during a rebounding movement to tend to unwrapand consequently expand so as to exert a braking action.

14. In a shock absorber, the combination of a pair of relativelyrotatable telescoping drums, one of said drums being mounted on one oftwo relatively movable members and the other of said drums beingconnected with the other of the two relatively mov able members wherebyto produce relative rotation of said drums in the movement of one memberrelative to the other, an internal expanding brake band mounted on theinner drum to have frictional engagement with the inside of the outerdrum, means for fixing one end of said band to the inner drum, the otherend of said band being free for expansion or contraction of the band,said band being arranged with respect to said drums whereby when theouter drum turns in one direction in the deflection of the vehiclesprings said band tends to wrap and consequently contract so as to exertlittle or no braking effect but arranged when the outer drum is turnedin the opposite direction during arebounding movement to tend to unwrapand consequently expand so as to exerta braking action, spring means foryielclingly urging the free end of said normally tending to turn theone. drum relabrake band in a direction to expand the tive to the otherand arrangeclzrluring: the hand to increase the braking action thereof.10

rebounding movement to be placed under In witness of the foregoing Iaffix my increasing load as the relatively movable signature.

members move apart, and means operating unclerethe loacl stored inasaiclspring means CHARLES A. STICKNEY.

